Inspired by this post Why is Sitecore getting so popular nowadays leaving Umbraco and Sharepoint behind I decided to explore further the reasons I think both CMS solutions can actually live happily as an eco-system as opposed to be considered competing.
First of all, I actively use both Umbraco and Sitecore as CMS solutions (though I get less call for Umbraco these days due to commercial reasons). I like both for their different reasons. I won’t even get into the reasons that Sharepoint sucks :D.
What Marina is saying is (in my opinion) true in that; I agree that Umbraco TENDS to be smaller scale implementations. I would debate the level at which that cross over between the likes of Umbraco and Sitecore are cost efficient to clients. Bear in mind – Umbraco has some big(ish) players in the marketplace, notably off the top of my head (previous or current) Heinz, Sandisk, Peugeot and Microsoft’s own http://www.asp.net.